Police are investigating a series of arson attacks in which trees and bushes in gardens were set alight.
The fires, in the Boythorpe area of Chesterfield, were started between Thursday and Sunday, June 13 and 16, with three of them on Grindlow Avenue.
A tree, fencing and hedges were set on fire during the incidents, with one of the fires spreading and damaging a number of windows and a car.
Witnesses saw two teenage boys on bikes in the area at the time the fires broke out.
One was aged about 13, with dark, straight hair, and the other was aged about 16 and had light hair.
In another blaze, on Hucklow Avenue, a conifer was set on fire and the flames damaged paintwork on a nearby house.
A hedge was also set on fire on the same street in another attack.
Sergeant Mark Church, who is responsible for neighbourhood policing in the area, said: “Whoever started the fires might think it is a bit of fun, but the fires could easily have spread and people could have been injured or worse.
“My officers are making every effort to find those responsible for setting the fires and action will be taken against anyone found to be involved.”